The generally low cancer rates in both Spanish and Indian populations in New Mexico are explicable on the basis of low level of economic development. No sites of cancer can be proven to be absent, due to small populations. Ten times expected rates of gallbladder cancer have been found in Indian women, and eight times expected in Spanish women. One-third expected rates of lung cancer in Spanish men may be due to delayed onset of cigarette smoking. Future work includes geneological studies of southern Rio Arriba County, the highest rate area for gallbladder cancer. Efforts will be initiated toward close determination of lifetime smoking histories in Spanish-American men.